Hydraulic extensible valve tappet



Jan. 29, 1946. o. w. METH HYDRAULIC EXTENSII BLE VALVE TAPPET Y FiledMarch 7, 1945 I N VEN TOR.

Patented Jan. 29, 1946 UNITED STATES PATENT OFFICE- HYDRAULIC EXTENSIBLEVALVE TAPPET I Orval W. Meth, Sacramento, Calif. Application March 7,1945, Serial No. 581,433 1 Claim. mil-iza-so) This invention relatesmore particularly to' an hydraulic extensible valve tappet for internalcombustion engines.

Among the object of the invention isto increase the power and efliciencyof internal combustion engines by increasing the volume of carburetedfuel intake during the suction cycle.

Another object is to increase the opening speed and lift of tappetvalves per unit of cam dis- .placement.

incidental noise and inefficiency of such clearance.

' Another object is to raise the valve head higher from the valve seatso as to present less obstruc- I tion to the incoming fuel mixture andoutgoing exhaust gases.

A further "object is to reducethe wear and noise of a metal valveseating on a metal valve The stationary piston 16 hasthe depending skirtl1 sliding freely within the lower chamber I2, with interposed sealingrings, such as IS. The

expansive spring I! interposed between the stationa'ry piston l6 and thebottom l0, normally holds the cylinder 3 depressedso that the bottom lrests upon the dwell interval of the cam 5 on rings '25, 2s.interconnected by'the bypass seat, by retarding and cushioning thedescent of the valve assembly; which has a like beneficial effect in thecam assembly. Other objects and advantages will appear as thedescription progresses.

In the specification and drawing the invention is disclosed in thepreferred form. But is to be understood that it is not limited to thisform because it may be embodied in modifications within the spirit ofthe invention as defined in the claim following the description.

In the one sheet of drawing, a valve tappet assembly is shown invertical section installed in a portion of the engine block, inaccordance with this invention. t

In detail the structure diagrammatically shown in the drawing comprisesthe engine block I, hav

ing a cylindrical guide opening 2, and the lateral vertical guides 3, 4,therein.

The valve tappet assembly is interposed between the cam 5 and the valvestem 6, that is surrounded by the spring 1, expandin between the valvestem guide, on the engine block I, and

the washer 8, bearing against the transverse pin 65 through the valvestem, to normally seat the valve K in the usual manner.

The tappet cylinder! slides freely within the opening 2 and has theclosed bottom l0, and the intermediate partition ll, which divides thecylinder 9 into upper and lower chambers l2, l3. This cylinder has thevertical slots ll, l5, registering with the guides 3, 4, in the engineblock.

the cam shaft 20. A similar spring as H may be usedin the upper chamberbetween the dividing wall I l and the inverted hollow plunger 23. Thestem 2! on the piston It has the transverse stop bar 22 adjustablymounted thereon and project? ing through the slots l4, l5 and abuttingthe tops of the guides 3, I.

The upper chamber l3 has the inverted hollow plunger 23, with the skirt24, sliding freely within the upper chamber with the interposed sealing21 formed in the wall of the cylinder 9. The plunger 23 has a smallerduct 28 within its wall and opening inside of the head of the plunger 23and through the skirt 29. The opening of duct 28 at 29 is betweenthesealing rings 25, 26. The oil line at 3| registers with the upper endof the passage 32 in the wall of the cylinder I. This provides a freecirculation of oil from the usual oil pressure system of the engine,from the line 3|,

through the passage 32, the lower chamber l2,

bypass 21,- the upper chamber l3, the 'duct 28 to the outlet oil line30, during the dwell interval of the cams as shown in the drawing. Thisoil pressure normally holds the upper plunger 23 elevated into contactwith the end of the valve stem 6, and the cylinder head 9 in pressurecontact with the cam 5*, without clearance or lost motion between thecam and valve stem. Any air bubbles in the oil pressure system wouldaccumulate in the top of the upper plunger 23 and escape into the outlet30. Thus assuring acornpact body of oil in the tappetsystem of theinvention. A'valve such as 3i in the inlet oil line 3| may be used toregulate the flow of oil to the tappet assembly.

The invention operates substantially as follows: The rise of the cam 5lifts the bottom of the cylinder 9. against the tension of the spring I9and stop bar 22. This lifts the whole tappet assembly and displaces theoil from the lower chamber i2, through the bypass 21 into the upperchamber l3, which has the same superficial area and capacity as thelower chamber. The oil filling the. chamber I3 lifts the plunger 23, andthe The upper and lower chambers are I and leaves practically noresidual burned gases The volumetric displacement from the lower chamber[2, displaces the plunger 23 upward higher and at greater speed than therise and speed of the larger cylinder 9. In this manner, increasing themere height and mechanical lift of the cam 5, if directly acting againstthe valve stem 6 in the usual practice.

In the present instance the valve rising faster increases the length ofthe time interval in the fuel intake cycle, increasing the fuel volumetaken into the engine cylinder during the suction cycle. The rise ofcylinder 9 upon the skirt I I of the stationary piston l6 shuts offthe'lower end of oil passage 32 at 33, and the rise of the skirt 24 onthe upper plunger closes the escape of oil through the line 30, leavingthe tappet assembly packed with oil to capacity.

As the cam begins its descent the lowering of the cylinder 9 under thetension of the spring l9 and the tension of the spring 1, provides spacefor-the oil being displaced from the upper chamber through the bypass 21by the expansion of the valve spring I, until the duct 28 again reg-This bypass open ing 21 being relatively small, acts as a dash isterswith the outlet line 30.

pot restricting the flow from the upper chamber l3 and retarding theclosing of the valve of the stem 6.- This retards the closing of thisvalve haust cycles; improved thermal efllciency due to an increasedvolume of cold fuel gases and .a more complete exhaust of hot burnedgases; less wear and tear on valve assemblies and valve seats, due toretarded closing and the absence of noisy tappet clearances. Motorbalance is improved and greater speeds are possible because of theimproved general performance of the reciprocating parts under betterbalanced stresses.

In overhead valve in the head systems having rocker arms workingdirectly on the valve stems,

X at the end of the intake cycle, thereby lengthening the suction cycleand increasing the volume of fuel gas taken into the engine cylinder.

When the hydraulic tappet assembly, according to this invention, isinterposed between the cam 5 and the stem 6 of the exhaust valve astheexhaust valve, which increases the exhaust interval. This improves thescavenging efllciency,

in the engine cylinder to dilute the incoming fuel of the succeedingsuction cycle.

Some of the advantages of this invention are, increased horse poweroutput, due to more efficient ,valve operation in the suction and exthepresent invention can be interposed between the cam actuated push rodsand the rocker arms; or otherwise applied to the various types of tappetvalves.

Having thus described this invention and its mode of operation, what isclaimed and desired to secure by Letters Patent is: a

In an internal combustion engine having. a block with an oil line with avalve therein, a cylindrical guide, and a cam and valve stem operativetherein; an extensible tappet assembly comprising a cylinder having sideslots through its wall and slidable in said guide with its bottomresting on said cam and an inlet oil passage in its wall registeringwith said Oil line and terminating near said bottom; and an outletpassage through said wall registering with, the outlet opening of saidoil line, whereby the passage of oil through .said line isstopped whensaid cylinder is lifted by said cam; a partition dividing said cylinderinto lower and upper-chambers,

